For example, many porous bodies made of aluminum are proposed as an electrode collector of an electric double-layer capacitor or a lithium ion battery, a filter for recovering hydrogen in a fuel cell, a refrigerant passage of a heat pipe for heat exchange, or a regenerator of a Stirling engine mechanism.
Conventionally, as such a porous aluminum body, a porous body obtained by forming an aluminum foil and a porous body having a skeleton obtained by sintering aluminum powder as observed in the following Patent Literature 1 are known.
However, there has been a problem that when a porous body is formed of these aluminum foil and aluminum powder, it is difficult to obtain a porous body having high porosity. On the other hand, the improvement in a porous body has been demanded because, in the above capacitor or lithium ion battery, better characteristics can be obtained as the open porosity of an electrode collector is increased, and similarly because, also as a refrigerant passage of a heat exchanger, the heat exchange efficiency is increased as the open porosity of the porous body is increased.
Therefore, the present inventors have proposed, in the following Patent Literature 2, a method for manufacturing an aluminum porous body having a three-dimensional network skeleton structure by forming a viscous composition using a mixed raw material powder obtained by mixing aluminum powder and a sintering aid powder containing titanium and the like, foaming the formed composition, and then sintering the foam by heating in a non-oxidizing atmosphere. According to this manufacturing method, an aluminum porous body having a high porosity of 70 to 90% can be obtained.
However, in the above method for manufacturing an aluminum porous body, there has been a problem that since a predetermined holding time is required particularly in the step of foaming a viscous composition, it is necessary to employ a so-called batch treatment, and it is difficult to perform continuous and highly efficient manufacturing as a whole.